Posted
by
timothyon Monday May 09, 2005 @09:29PM
from the what-about-all-those-batteries dept.

Jason Siegel writes "Hybrid cars seem like the answer to rising gas prices, increased pollution and growing dependence on foreign oil, yet EPA tests have failed to produce reliable mileage estimations for consumers. Dependable fuel economy figures are now available at GreenHybrid.com, where hybrid owners have logged over 5,000,000 miles of driving information in real-world conditions. Unlike government tests and individual accounts, the database analyzes thousands of actual experiences to provide true mileage statistics." Read on for the rest.

The hot-selling Toyota Prius averages 48 miles per gallon among over 150 cars from across the country, with most drivers achieving between 45 and 51. The V-6 Honda Accord Hybrid delivers 30 miles per gallon while Ford's Escape Hybrid SUV averages 28. All hybrid owners are encouraged to post their data for these and other cars on the Internet's largest hybrid mileage database.

Reliable fuel economy figures are increasingly important as consumers explore their options in an emerging hybrid car market. Hybrids, like the new Lexus RX 400h, pair combustion engines with electric motors that recharge while driving to improve gas efficiency. "Until lately," said GreenHybrid creator Jason Siegel, "consumers have associated hybrid vehicles with a small niche of fuel-conscious environmentalists, but today's hybrids offer the best combination of high performance, great mileage and luxury features of any cars on the market."

You know, I'm starting to wonder if some of those gas saving tips like "start and stop slowly" have been backed up with real world testing. I just spent the last three weeks testing the hypothesis that "driving smoothly" (ie, starting up slowly and anticipating stoplights, etc. saves a lot of gas. Here was my test. By the way, I have a 2004 Honda CR-V that gets a rated 24 MPG Highway:

Drive through another tank of gas, but this time very agreessively.
Basically, I floored it when taking off and took the car to the max.

Make same MPG calculation at end of tank.

You know what I found, I got 25 MPG in BOTH cases. In fact, I got slightly better milage when I was agreessive. Granted, this was not completely scientific, but it made me wonder about doing more accurate testing. I expected to see a 5-10 MPG difference. To follow up, I drove the last tank at a normal "in-between pace".

I was talking to someone at work about it and they thought that maybe today's engines are tuned so well and change with different environments that it doesn't make a difference. It only makes a difference if you are stopped a lot like in traffic jams.

Anyone in Central Indiana want to join me for some more scientific testing?

Ok, that is what I've heard a lot of people say as well. I thought I had the same intuitive feeling about "driving smoothly" as well, until I measured it. Maybe you should measure it sometimes. Of course, driving faster has other incalculable impacts such as paying for tickets, higher insurance and accidents.

Mass carnage was predicted when the double nickle speed limit was dropped. In fact the accident rate WENT DOWN.

There were several reasons for this. N.B., all of these were predicted by the proponents for the change, but dismissed by the safety "experts."

First, anyone with a clue knows that the biggest threat on the highway is traffic traveling at different speeds, not the absolute speed. People tend to stay in their own lanes - and can even comfortably stay in the right hand lane - if everyone is travelling at about the same speed. But if there's a 20 mph range (which was common in the interurban areas of the square states) there will be a lot of lane changes even when traffic is relatively light. At those speeds just tapping a car may be enough to cause the driver to lose control.

Second, a realistic speed limit actually lowered the speed of the fastest drivers. A driver going 20 mph over the posted speed limit doesn't have much motivation to avoid going 30 mph over the posted speed limit. But the same driver at the same original speed, if it's the speed limit, will often stay at that speed.

Finally, these roads were designed for traffic going at ~70 mph. At those speeds the road has just enough variability to keep the driver's attention. At the slower speeds the roads are mindnumbingly boring and the driver's attention tends to wander. You wouldn't think it would make that much of a difference, but I've driven between Denver and Seattle at both 55 and 75 and there is absolutely no comparison. (I-80 thru Wyoming and the Columbia River Gorge still suck because they were long, straight flat segments.)

That's why the death rate went down when the speed limits were raised. The annual death rate is climbing again, but that reflects more passenger-miles.

P.S., the Colorado Dept of Transportation will actually adjust the speed limit to match the drivers, not the other way around. They feel, reasonably, that thousands of drivers will make an informed decision about the best speed for a segment of road. Sometimes their hands are tied because of regulations, but I've seen them change the speed limit on other segments.

"In fact the accident rate WENT DOWN.""That's why the death rate went down when the speed limits were raised."

Not that I disagree at all, but there is a common assumption or mis-conception that you seem to be repeating here, unless you have a separate source. A lower accident rate does not mean a lower death rate or vice versa. It might be true in this case, I'm not sure.

The argument about relative speeds being the problem probably has a lot of truth in it; I've read research in this area and it certainly seems to be a factor. However, reducing the disparity by raising the speed of the slower drivers means that there is much more kinetic energy on the roads, especially with kinetic energy increasing with the square of velocity. (20% faster speed means 44% more kinetic energy.) This is further exacerbated by a trend towards larger vehicles, such as SUVs, since kinetic energy is also proportional to mass. In an accident this energy must be dissipated and the amount of damage will generally be related to this energy.

So, while accidents may happen less often, the average and total damage caused in an accident may increase, including death rates. Accident rate is only part of the equation. Again, the death rate may have indeed dropped, but it isn't a given just because the accident rate dropped.

Something like this is really hard to qualify because there are so many factors involved.

Due to structural crush zones in cars, additional airbags, antilock braking systems, door beams, and other safety features in even cheap cars, accidents are much more survivable than they were even 20 years ago. However, with the trend in this country towards gigantic SUVs for every soccer mom, it may be equally counterbalanced.

The US DOT would have you believe that slower is safer, which it may be in densely populated urban areas. However, in mind-numbing interstate travel (I just made a 742 mile trip last Tuesday and again on last Saturday), you want to go as fast as your car feels safe traveling. This does increase your attention and focus, because you are forced to react to changing terrain more frequently and you realize the margin of error shrinks at higher speeds. I.e. you achieve a slightly higher 'pucker factor'.;)

There is a limit as to how fast you can safely travel which is mainly governed by how quickly you can stop. Sport Compact Car magazine recently reviewed a race-ready Mitsubishi Evolution 8 with upgraded everything including a beefed up braking system. The stopping distance from 60-0 was an unheard of 98 feet. From 70-0 it increased slightly to 135 feet. Now, from 80-0 we see a shocking increase to 179 feet. 20 mph, 33% faster and you effectively double your braking distance! Keep in mind this is on an exceptional car, real world, average cars come nowhere close to these numbers. Stopping from 60mph in 98 feet would sling the snot out of most people's noses.

Perhaps you're right about 20% faster speed nearly doubling kinetic energy, as that's what the braking system is being forced to deal with and would definitely cause those numbers to nearly double.

One of the great traffic safety myths is stopping distance. Who cares if your stopping distance is 200 feet or 300 feet?

Personally, I think putting so much emphasis on stopping distance is a mistake. We spend a lot of time teaching drivers that they need to be able to stop before they hit something, and that's not true. You need to be able to STEER to AVOID the accident. I've witnessed on more than one occasion a driver get into an accident that could have been avoided by NOT braking and turning (doing

Virtually every accident I have witnessed that was clear caused serious property damange, injury and death (seen a few of those, unfortunately)... nearly 100% of those, if not 100% were people trying to swerve around slower or stopped traffic.

Why is that? People in the US are not taught how to control a car, they are only taught how to interact with other cars on the road. Watch someone who is a professional or amateur race driver (who understands vehicle dynamics at the limit) in those situations -- they react totally differently. Threshold brake, keep the ABS from engaging, and stay in a straight line. If you can't scrub the speed to the point where the impact will be a non-event (5mph), you were following WAY WAY too closely. Better to hit the car softly than risk oversteering into it, or worse understeering off the road or into another traffic lane. Once a car starts to lose traction, it takes a very skilled driver to make it go where they want it to.

If you don't know the reasons going 100mph is unsafe for most drivers no matter what the road conditions, you're not in the "knowledgable driver" camp. 100mph is dangerous in any situation in 99% of the cars on the road. Its not how the car and driver can handle expected situations, its how that car and driver can handle an unexpected one. In virtually every case, at 100mph they can't.

Two speed limits isn't the answer. Requiring something more than ten hours of on the road driving and 30 hours of classroom time is the answer. Require limited traction training the way many european countries do. Or maybe just even mention the concept of a traction cirle to young drivers and explain why their lives may depend on them understanding it. A properly trained driver can be in just as much control of a car with four wheel sliding as a badly trained driver on dry pavement.

One of the great traffic safety myths is stopping distance. Who cares if your stopping distance is 200 feet or 300 feet?

Okay, I agree that in some conditions stopping distance isn't the be-all and end-all of safety, but I still care deeply. The problem isn't "good" drivers. The problem is average-to-poor drivers. Knowing what to do in a panic and actually doing it are two very different things. Almost everyone knows you "steer into a skid" but how many people do that instinctively?

The problem is that most drivers are going to react linearly to threats. Basic amimal instinct is to stop and assess. Steering out of a situtation, or even speeding up to avoid a crash are often viable options, but they require that the driver have awareness and confidence not only of the road in immediately in front of them, but also to the sides and behind them. The simple truth is that 90% of drivers don't pay that sort of attention consistantly. When something unexpected comes up, they hit the brakes. "Slow down, let me think" is too deeply ingrained of an instinct to train around.

Traffic laws have to be made for the lowest common denominator. Unfortunately, this is often the distracted parent in a huge vehicle full of screaming kids with a cell phone in his or her ear. I don't like it, but I don't think there is anything which can be done about it.

"Almost everyone knows you "steer into a skid" but how many people do that instinctively?"

Especially when you're driving a friend's car and all your reflexes are trained for your own front wheel drive compact.

I'm not proud of it, but by the time my brain had recalled what I learned in driver's ed about handling a skid in a rear-wheel, we were sitting in the ditch, and my girlfriend had a new embarassing story to tell her family.

True there are many times you could steer out of an accident. However there are many more times when you cannot.

A habit of hitting the breaks hard may sometimes result in an accident that is avoidable. However it will never result in an accident much worse than the one you were trying to avoid.

When you steer you have to prevent a rollover. You also have to have a clear place to go. Searing into oncoming traffic changes a 'simple' read end to a head on. Steering into a ditch may often mean hitting

Let me tell you a little secret the EPA doesn't want you to know... at idle, you're NOT MOVING. When you're not moving, all the gas your burning is not taking you anywhere. So if you sit in your driveway with the car idling with a full tank of gas, and wait till you have enough gas to drive one mile, then you drive that mile and run out. Your car was just getting (assuming it's a 14

Screw hybrids- just think how much gas we could save if we made all the roads downhill!

You fool. They've been working on this for YEARS. If you don't believe me, ask any old person how often they had to travel uphill back in their day. Most of them will tell you more often than not, it was uphill BOTH ways. I'm sure you've heard it. These days, on average, you usually go uphill around 50% of the time. I'd say thats a drastic improvement to our road infrastructure. It's gonna be awesome when they finish.

I'm glad to notice you are considering wind resistance as well as the difference in stopm and go trafic verses continuous highway driving. The bigest factor in speed verses fuel usage would be resistance.

Wind resistance, starting to move resistance, going up hills resistance, and the difference the weight has on thse resistance play a crucial role in gas miliage. I have a van and with it fully loaded with camping and hunting gear i average around 1 or 2 miles per gallong less. A slight breeze will drop my miliage another 1 or so miles per gallon on the same 200 mile trip. If it is realy windy, i can expect a little more drop. Newer stream lined cars wouldn't see as dramitc effect as i do on the wind but might see more of an effect on the weight because thier engines typicaly are smaller. Going up some hills, I tend to pull away from other trafic even when pulling a boat or 4 wheelers. I can also get better miliage in town when my tanks are half full (less then 20 gallons compared to 45 gallons total full) with the same cargo. My overdrive in town causes me to use more gass too. I think it is because the high gearing requires more fuel to maintain the same power ratio to the ground.

On the same note, While in fith gear, if you are having to depress the excelorator more to maintain your speed then you would in fourth gear, you might actualy use more gass then if you increased the RPMS and ran at a lower gearing.

When i drove a class 8 tractor trailor the manufacturers of the engines (detroit deisel) gave us training on fuel econemy. Some basic bullet points were that the engines have a peak power to torque ratio were when the rpm making the most power croses the rpms making the most torque resulted in the best fuel econemy. The transmisions and rearends were geared with this in mind alng with the rated top speed. Granted with a deisel engine the RPMs were alot lower and basicaly limited to around 2200 - 2300. We usualy shifted and attempted to keep them around 1700-1800 rpms.

Without idle time (as you mentioned earlier) I could average about 8-9 miles per gallon running at gross (79-80,000 lb). This was up from 4.5 to 5 miles per gallon before we had our little talk. That was acording to the little engine computer read out on the dash. Durring real windy times i actualy get better miliage at slower speed but could run 70 - 80 mph most the time were the speed limit allwed. On a calm day the lower speed would be less then 1 half a mile per gallon because of the gearing. If you could place your car on a dino and check the torque and power rats, you might find an ideal range to drive long trips and realize a big fuel savings.

Another point was the electronic cruise control. Running with the cruise control allowed engines computer to caculate the exact amount of fuel needed to maintain speed were driving by foot would cause speed to fluctuate enough that the driver would over compensate the throttle and apply too much power to maintain speed. My buick's cruise control saves fuel on long trips much the same but my van's cruise is too old to have much difference (rebuilt and pumped '84 chevy 350). My semi truck would see around.5 to 1 mpg more fuels econemy then without using it. One mpg doesn't seem like much but it adds up. Especialy if you are getting lower mpg.

Newer streamlined cars wouldn't see as dramatic effect as I do on the wind

That's true for wind resistance from weather-related wind, but actually, small fuel-efficient streamlined cars are quite sensitive to increased wind resistance, moreso than larger vehicles, at least when it comes to added wind resistance from bikes or luggage on the roof, for example. Even roof racks without anything on them can affect mileage noticably- I remember an old friend's 83 Honda Civic which got 38 MPG with empty roof ra

Which is exactly why the speed limit when from 70 to 55 durring the oil crisis. Someone will correct me, but wind resistance is cubed every time you double your speed. Our old '84 caddilac with trip computer got 25mpg at 64mph, but got 17-19mpg at 70mph. Closer to 28mpg at 55mph.

Which is exactly why the speed limit when from 70 to 55 durring the oil crisis. Someone will correct me, but wind resistance is cubed every time you double your speed. Our old '84 caddilac with trip computer got 25mpg at 64mph, but got 17-19mpg at 70mph. Closer to 28mpg at 55mph.

Every time you double your speed, wind resistance quadruples. It goes with the square of the velocity.

However, that's not the whole story by a long shot, which should be obvious. If the slower you go, the better gas mileage you get, you might think you get infinite gas mileage at a standstill. Of course, you don't.

What makes the difference, then? Gears. See, your engine is extremely efficient in an RPM band - around the torque peak (called the power band). It's most efficient at the bottom of that power band. The gears don't actually help anything - as you learn in basic physics, simple machines don't change the amount of work that needs to be done. What they do is allow the engine to run at a more efficient RPM for a given speed.

So what gears do is put peaks in the fuel efficiency curve. Depending on how a car is geared, 55 mph can be very inefficient, because it could be at the worst spot below the power band, which it is on my 93 Mazda. 55 mph gets me 28 mpg, whereas 65 gets me 30, and 70 gets me 34. 75 gets me about 32, and 80 gets me about 30 again (this is all measured).

It's not just as simple as slowing down. You have to know how your car is geared - if it's got an overdrive, it's very possible that going 55 could hurt your gas mileage via engine inefficiency more than it helps via aerodynamics.

That doesn't mean that 34 is the best gas mileage I get, of course. My peak gas mileage is in the mid-40s, in the peak of the previous gear (if I lock it into 3rd via the shift lock), where it's about 36-37 mpg. At lower speeds, aerodynamics losses are well below rolling resistance, so going slower doesn't help.

I think you need to run some more tests there, as you should be able to do significantly better than that.

For example, if you leave your car parked in the driveway and walk, you should get near infinite fuel efficiency at 0 kph. You only have to worry about evaporation and the natural breakdown of the fuel in your tank.

(Sorry -- the mathematician in me decided to come out and be a smart-ass. The physicist in me would like to point out the the mathematician that we can do even better by putting the car in neutral while the engine is stopped and pushing it off a cliff -- you'll get ~9.8m/s^2 of acceleration without burning any fossil fuels whatsoever! Some days I just can't help myself...).

One of the things I learned when dealing with wind turbines is that double the wind-speed roughly equals eight times the power. Order n cubed. This doesn't work at very high or very low wind speeds because of turbulence and cavitation and similar effects, and goes completely wonky again near the speed of sound in the medium, but for highway-type speeds it's bang on. It may also be different for (mostly) non-rotating cars, but it is indeed worse than n squared once you get above about 50km/h.

That's because most transmissions in production cars have their highest geared tuned so that the engine's in its RPM sweet-spot around 60-70mph; after that, the amount of gas per RPM starts to increase considerably more.

I'm curious as to just how high the grandparent kept his RPMs when he got similiar gas mileage driving timidly and agressively. Also, where has anyone heard stopping slowly increases mileage? Maybe in a car with regenerative breaking, but certainly not in a good ol' ICE powered car. If your foot's not on the gas, only idle gas is going to the engine (unless the computer is doing something, but it shouldn't affect that much). Unless I'm missing something, I can't see how slowing down gradually will increase anything beside the frustration of the driver behind you because you're not getting to a stop light quicker:-P

The only reason stopping slowly helps MPG is actually similar to the concept of regenerative braking, albiet vaguely.

When you stop abruptly, you will arrive at the stoplight more quickly (higher speed for longer) therefore there is a greater probability of it still being red when you arrive at it, therefore you are more likely to be at ~0MPH, thus requiring to accelerate your car from 0 to whatever your cruising speed is (hence more energy and fule needed.)

If you ease off the accellerator when you first see the red light, you are a) not burning as much gas on your approach to the light, b) less likely to come to a full stop, and thus will have a smaller overall change in speed, less power required to return to cruising speed, less gas used. On the flip side, with this technique your chance of slowing down at a light is near 100% whereas in zero traffic, the abrupt stop method does give you a chance of zero change in speed, but you can only rely on that if you know the light timing and there's no traffic ahead to make you slow down anyway.

Incidentally, when I slow down earlier, and roll up to the red light at 20mph, still at speed when it turns, vs hitting it at 45 a few seconds sooner and needing to stop all the way, I find by a block past the light I've passed virtually everyone who was stopped at it, and so in addition to being energy efficient I've increased my average speed too.

Make sense?

Re: last line of parent: There is no benefit, as described above, to "getting to a stop light quicker" if it is red; hence the driver behind you has no real reason to be annoyed. But yeah, I'm sure he will be. Ignorance here is less than bliss.

Actually, modern EFI engines turn off the injectors when at zero throttle opening above some RPM level.

My car, turns off the injectors when coasting until engine speed drops to 1500RPM - theres a very faint-but-detectable jolt when they are turned back on. This doesn't hurt your engine because there's no fuel to burn at all compared to a lean mix.

BP Ultimate fuel questions [bp.com] Q. Why five tankfuls to clean up a dirty engine?
A. With increased detergency, Amoco Ultimate from BP will clean up engines with deposits in about 1,500 miles of use at an average of 300 miles per tank. Those five tankfuls will restore the engine to its previous level of performance, and with continuous use, Amoco Ultimate will keep that engine running cleanly.

Q. Why don't you apply the increased detergent additive in all three grades?
A. We offer cus

You probably implied why, but just to make sure, let's state why: The air drag your car feels is proportional to the square of speed. Stick your palm out the window to test. At 1 mph almost none of the gas is spent on fighting air, because the air has time to get behind you. At such speed your gas goes to fight friction in the tires bending and relaxing, and the pistons, cylinders, gears rubbing up against each other inside the engine. But at 90 mph a very significant portion is spent on air drag friction on top of the tire and internal engine friction. The actual formula is

F=1/2 * A * Cd * r * V^2

where

F - is the force pulling your car or your palm back

A - cross sectional area of your palm or car

Cd - is the drag coefficient dependent on shape of your car or palm - i.e. do you look like a parachute or a bullet to the incoming wind, because even if you have the same square footage area facing the wind, its shape matters

One thing that does make a difference is how fast you drive on the highway. I know I get much worse mileage driving at 80-90 than I do at 60-70.

I have a couple of empirical observations. These observations were made in a 1998 Subaru Impreza OS, 2.2L 4 cyl. boxer engine, 4-speed automatic, AWD. Some of the observations I have also made with a 1999 Chevy Prizm, 1.8L straight-4, 3-speed automatic, FWD.

Normal driving on my commute, a six mile trip involving about one mile of 65MPH on a freeway, but most

Wind resistance goes way up when you put the windows down on a car. On some cars it is much worse than others, depending on the aerodynamic shape of the car/windows.

At highway speeds, running the air conditioner is almost always going to be more fuel efficient than putting the windows down.

At slower speeds where wind resistance doesn't really come into play. cruising down residential streets at 25 MPH or stuck in stop-n-go traffic, the AC will burn more fuel than having your windows down.

A lot depends on how much time you spent on the highway and what the weather conditions were. Also, how often is someone ahead of you at the light? For me, it's rare to be first in line, and you can't accelerate any faster than the car ahead of you does...

I've actually heard that it may be better to accelerate quickly, if you know you're going to get to your target speed and stay there for a while (As opposed to stopping at another red light in 500 yards).

I'll second the driver that said higher speeds make a huge difference. The Utah desert at 95-100 gave me terrible gas mileage, but it sure was a fun way to get to Vegas.

While timing things so you avoid getting up
to 80 km/hr only in time to have to stop for
a red light makes sense, avoiding hard acceleration
is a bit of an anachronistic piece of advice.

Old cars were carburated. When floored,
lots of extra fuel would get dumped in the
carb, and any that didn't get burned in the
cylinders just got dumped down the tailpipe (possibly igniting,
causing exciting backfire noises).
So in the 70's oil crisis, we were all
told to accelerate gently.

It takes more energy to accelerate quicker than it does to accelerate slower.

You should review your freshman physics, in particular, kenetic energy [wikipedia.org]; E=½mv×v. While no car is ideal, there is no fundamental reason that a car should be less efficient at lower power levels. At any RPM, there should be an optimally-efficient power output, so anything other than that will produce sub-optimal efficiency.

Of course, if you are driving on the freeway all the time, all of your fuel use will go to f

It takes more energy to accelerate quicker than it does to accelerate slower.

As a blanket statement, this is false. Going from zero to sixty in ten seconds may end up requiring more work than doing the same in twenty seconds. However, depending on the engine, the gears, the wheels, the road, and all sorts of other factors, it may not. It's a complex problem that can't be solved via simple analysis.

Sorry, not any car. Being in a hybrid article I feel no problem posting this: at least for low speeds, you're dead wrong. I can accelerate aggressively from the light, and reach 40 mph, let go of the gas, and drive on battery for the rest of the 16 seconds, meanwhile if I accelerate slowly up to 40, assuming the gas engine is on during acceleration, I'll end up using more gas.

My assumption, which you may not be making, is that you're also factoring in the fact that you can be operating at idle/no engine

There are many dealerships that do not add a markup. If the one near you does, just say "Sorry, but I refuse to pay your luxury tax. You have lost any future business from me." and go somewhere else.

Call all the Toyota dealers near you, even 200-300 miles away, I can almost guarantee that you'll find one in stock, at MSRP. (I only had to wait 2 days for mine. And it wasn't even 'ordering', it was calling all the dealers on Saturday, getting on their 'lists', and getting a call back on Monday saying they had 2 in stock that met my requirements (Blue, Tan, or Green, 2004 Packages 7 or 9, which are now called 5 and 6.) I drove a Blue package 7 Prius off the lot a mere 2 days after starting my search. (I could have had a top-of-the-line package 9, but it was in 'Tideland Pearl', which I mistakenly thought was green, it's more of an olive drab. So I picked the lesser-package 7 in blue, because I actually liked that color, and the extra features weren't important enough for me to want to wait.)

The Charade is a tiny 2-door car with no power and a manual transmission. The Prius is a decently peppy 4-door midsize with an automatic (well, continuously variable) transmission.

If you want to compare hybrids to nonhybrids, compare similar vehicles. The Insight averages 63mpg, 40% better than the Charade - and that includes both the automatic and standard Insights (the standard Insight does even better).

Before anyone gets confused, I just want to point out that the Accord hybrid is not supposed to be super-efficient like the Prius. It's the top-of-the-line Accord, and the hybrid power is mostly used to increase performance while retaining similar fuel economy to the slower models. It's quite zippy; IIRC it has better 0-60 times than a V6 Mustang.

Quite agree. The Peugeot turbo diesel option (same Bosch direct injection technology) keeps setting world records. Their 307 just got 3.49 litres per 100km's (or 81.16 mpg in old money) according to this [drive.com.au] website. They averaged 1,700 Km per 60 litre tank!
Why add all the complication of hybrid technology, or why not couple an engine like this with hybrid technology?

The one thing diesels tend to do poorly on is emissions, and California's emissions requirements are one reason automobile manufacturers are investing in hybrids. But even in the non-diesel arena, raw mileage isn't everything when it comes to this sort of thing: the Honda Insight gets much better mileage than the much heavier pre-2003 Toyota Prius, but the Prius has lower carbon emissions because the (very heavy) planetary gearing transmission lets it balance the load on the gasoline engine so that whenever it runs, it does so in the sweet spot to minimize pollutants.

A diesel electric built along the lines of a locomotive would be interesting.

For those who don't know in this case the diesel engine is basically just an electric generator that powers the electric motor. Because as a generator it can run at a constant speed it's even more efficient than a traditional diesel. It works for trains, I'd guess it would work for cars/trucks/SUV as well. GM/Allison has built buses this way that see a 60% MPG increase vs conventional diesel buses. If a Chevy heavy duty pickup sees a similar increase that would put it near 40 mpg on the highway. Pretty good for a 1 ton truck.

Another thing we haven't seen quite yet is the turbine hybrid vehicle. We've had turbine powered vehicles in the past, but rather than gearing-down the turbine, I believe that you should be able to gain power from the rotating part in the turbine -- just by itself. I would assume that the unit would maintain it's rotation, and fuel/air ratios. I think capacitors come more into play than just batteries, as other electric-only cars have had.

California doesn't prohibit private ownership of diesel cars -- you can drive a beater diesel Mercedes or Volvo if you want -- but it does have high emissions standards on new privately owned diesel vehicles. That said, auto manufacturers are aware of this and I believe make California-spec diesel cars.

Actually, diesel automobiles (such as the VW TDI, Peugeot 307 and SMART car) are typically amongst the lowest greenhouse polluters according to the Government of Canada [nrcan.gc.ca] and the EPA [epa.gov]. Even urban particle count measurements have automibile diesel engines scoring well compared with gasoline engines. You are most likely confusing the modern diesel automobile with older trucks widely used in the transportation industry.
I'd be quite interested in the 'stark facts' you suggest. Perhaps you can post a link?

It appears I was wrong about the particulates... This [caranddriver.com] explains in more detail. I'm not too sure I agree with the doom-and-gloom but perhaps the US has such poor fuel that this is true.

EPA estimates have never been really useful indicators of real-world results, nor were they intended to be.

What they do provide is a car-to-car comparison that is consistent regardless of driving style, load, weather or other conditions. When you compare EPA mileage statistics, you're comparing apples to apples.

Hybrids throw a monkeywrench into the mix, so we'll probably see an adjustment to the EPA methodology at some point.

I have a 1978 British Mini (the old ones) and the gas mileage is anywhere between 50 and 60 mpg. Here we are almost 30 years later and we are getting- lower gas mileage?

Granted the Mini does not weigh anything and lacks AC- still. The 1 liter engine kicking out 55HP (in my slightly modified engine) is more than adequate to move such a light vehicle. Add to that a suprisingly roomy interior (it will seat 4 people comfortably despite being only 10 feet long) and a car that will corner like a go kart and you have to ask yourself what the auto industry is thinking. Not to mention being able to park _anywhere_:)

We have materials today that Alec Issigonis (the guy who created the Mini back in the 50's) could only dream of- lighter, stronger and easier to shape- and yet cars today are far heavier. We get worse gas mileage- sure the cars are more powerful but then again they have to be. I realize some of this weight is the result of safety improvements and the like but it just feels like there has to be a middle ground.

The answer is simple: Americans like Big and Cheap. Look at any city in the US. Every town is full of the same giant strip malls *full* of Big Box Stores, filled with fat people eating giant portions of fast food from their gas guzzling, crappy Ford Explorers. I'm American. Sadly, it's true. Almost the whole country is now like this.

People don't like small cars (not that this is acceptable or anything, just telling it how it is)

Most people want AC, power steering, and other standard luxuries

While the weight of the car drops as the engine gets smaller, people tend to get bigger. An extra 500 lbs of people can really put a dent in your performance

People can't drive standard transmissions worth their life anymore (and torque converters are only so efficient). Step-tronic ("robot shifted standard transmissions") transmissions just add to the weight.

Some random reasons. I'm defending any one of them, but just adding fuel to the fire.

The amount of energy used by an average automobile over its lifetime (manufacture, operation, maintenance and disposal) that comes from the gasoline used to drive it is only a fraction (around 1/5 to 1/3) of the total.

A hybrid does reduce the total energy consumption of a car over its lifetime compared to a conventional car, but not by all that much. It still takes all the same materials and manufacturing processes to build, and poses the same disposal problem once it wears out.

The answer is a combination of fewer, longer-lasting, more-efficient cars, and less driving.

It still takes all the same materials and manufacturing processes to build, and poses the same disposal problem once it wears out.

Well, at the risk of sounding like a Toyota ad, the Prius is built using 90% recyclable materials. For the soundproofing, they literally use shredded material from old cars. They use a tenth of the lead and a tenth of the PVC they were using in their cars in 1996. They even use plant-derived bioplastic for the floor mats.

Fine, now a gallon of gasoline contains 125,000 Btu [vigyanprasar.com] of energy. That's about 37 KWh.

If your car's getting 40 mpg, and if you're driving it 10,000 miles per year, you're using 250 gallons of gasoline a year. 250 * 37 KWh is 9,250 KWh per year.

Drive your car for three years and you've used more energy than it took to build. If we wanted to compare the "theoretical maximum" amount of energy that can be extracted (at 50% efficiency) from gasoline, you're only looking at a year and a half. Any car built in the last ten years should last five to ten times that long.

...is the visual display which tells you the target mileage given your current acceleration.

I drove a 04 Prius for a few months and found that the display which tells you the fuel economy you're getting is very helpful. After about a day you realize that speeding up hills eats at your economy and braking appropriately helps too.

If all cars had this feature, fuel economy would be increased. Regardless of the fact the Prius has a hybrid engine, low rolling resistance tires, etc, this simple display is a big psychological factor.

Most people never realize their driving habits affect fuel economy because it only hits them every two weeks at the pump. By that time they never link it to how they brake or accelerate. By closing the feedback loop, you start to change your driving habits.

Only expensive cars seem to have this feature, yet it's ridiculously simple to implement off a modern ECU. I wish they'd make it standard equipment and not a luxury feature.

2. Long-term reliability and replacement costs of hybrid system (especially the batteries). 5 or 10 years from now, are these cars going to be proven as reliable as their traditional combustion-engine brethern? Or are they going to be visiting the shop more often to fix issues in their hybrid systems, replace their batteries (which do have a pre-determined lifetime), or whatever??

The answers will come in time, but not from the data of 150 measly vehicles.

PS - The dork who compared a 40-year old car to a modern vehicle just doesn't get it. Modern vehicles meet modern safety standards, including such luxuries as airbags, enhanced structures that help prevent serious bodily injuries, and a little more leg room. Yes, if I built a go-cart, I could probably also get 50-60 MPG. But I wouldn't be stupid enough to drive it on I-95.

I think you have a point about reliability for the Ford... but given Toyota's reliability reputation, and the Consumer Reports rating which put Prius #1 in customer satisfaction, I think the Prius is a pretty safe bet.

Toyota gives the batteries a 10 year warranty. The gas engine is the same as the engine in a Corolla, just adjusted to run on a different combustion cycle. There's no gearbox, so that leaves the transaxle and computer to worry about... Personally, I'll take that bet.

or are those numbers pretty piss-poor for hybrids? I remember when the Insight was pimped as having 70mpg and the Prius 60. Nobody comes close to those figures now. 30 mpg for a V6 Accord? The normal Accord gets only 7 mpg less (ajusted from vendor inflation [fueleconomy.gov]. Hybrid:37 Normal:30). The variance in the Escape is less than that.

How can these cars be touted as environmentally friendly when you could easily increase your gas mileage by driving a 4-cylinder instead. That way, you get the gas savings and you aren't throwing away a huge battery full of toxic waste when you're done.

My Porsche 3L Porsche 968 (at 11 years and 91,000 miles old) gets 32+ MPG on the freeway, and mid-20s in city traffic. My BMW motorcycle gets over 70MPG. (Granted, those of you who don't live in SoCal probably can't motorcycle commute 49 weeks out of the year the way we can;) I expected a lot more out of the Accord. (I don't expect anything from Ford, except maybe mechanical problems.;)

Hybrid benefits are overrated because of the weight of the vehicles. This decreases much of the benefit.

Take a 1992 honda civic chassis. Look for one of the efficient models (Vx, others). You want a 5spd. They are very easy to work on, and very common. Engine reliabilty is great.

These cars were commonly available with no power steering, and no AC. Power locks and windows? Ha!

Strip the car bare. Gut it. Install some lightweight racing seats. You just saved a lot of weight. And gained a lot of cargo room!

Have the engine reworked. Lots of manuals for this; it can be done in a weekend, with a weekend of preparation. You'll need to clean all the fuel filters, injectors, and install all new ignition components.

Install a wideband o2 sensor with a car monitor. Consider an EGT meter as well. This will let you track your mixture inside the car to see if you're running rich and/or overheating your exhaust valves.

Install a VAFC, a small computer that tweaks the fuel settings. Most of the time these are used for power, but you're going to use it to dial out as much gas as you can without running too lean.

Although I am the proud owner of a new Toyota Prius, I can unoquivically say that hybrid cars are not the answer; they are a stop-gap measure that may extend the period of time that oil is a primary fuel on the planet Earth. However, they are too little too late; I have the income to allow me to "do the right thing" but really, I should either move closer to where I work or take public transportation to really do the right thing. I'm not going to do that, and my neighbors are going to bitch about how much it costs to drive their SUVs but they don't look like they're selling them anytime soon.

So who cares what the mileage figures are? The hybrids are far better than the other cars on the road, but they won't amount to any appreciable percentage of the cars on the road until gasoline is priced high enough to force it, or the government mandates it. Neither is going to happen, so unless there's some miraculous breakthrough that provides a cheap source of hydrogen pretty damned soon, it's all moot.

Yeah, I'm kinda pessimistic about energy usage in the U.S. We're kinda like the guy who jumped off the really tall building saying, "Nothing will happen!" who could be heard saying as he fell past each floor "So far, so good!"

Still, I bought a Prius to support the company that made the R&D investment to give us a stop-gap solution, even if we're not moving to a viable alternate energy source with the urgency we should. Meaning, I don't know if my partial gesture will matter, but it's better than driving the car it replaced at half the mileage.

Toyota is doing what GM and Ford couldn't do. It's letting it's customers help fund it's R&D related to the transition from gas to electric.

Future cars are going to be all electric. That's all there is too it. Why? Simplicity. It takes a great deal of effort to design a mechanical structure that can transmit anywhere from 200-600 bhp from the front of the car to the back. You lose efficiency on the drive shaft, at the transmission, etc.

The end game of cars is going to be where the motors are built into the wheels. The power plant is interchangeable (and inconsequential). When you brake, all four wheels will capture the energy into some sort of temporary energy storage device.

1. Electric engines and direct coupling are good and fine, but the problem nowadays is that, basically, batteries suck. They don't come anywhere _near_ the energy density of gasoline or diesel.

Which doesn't just limit your range in an all-electric car, but also makes the whole car heavier. It means you actually need more energy to move at the same speed and over the same distance.

Hybrids acknowledge that reality. The electricity in a hybrid ultimately comes from gasoline too, and is only used so often.

I.e., expect to see hybrids instead of all-electric cars for a long time.

2. The whole "waah, but oil is going to end" premise is bogus anyway.

Yes, fossil reserves will eventually end. But here's the fun part: we already know how to produce synthetic oil. We've known it for a long time. And not just theoretically: Germany's WW2 tank warfare was _based_ on synthetised fuel. It wasn't cheap, but it did keep the panzers rolling nevertheless.

That's really the only thing that keeps us using fossil fuels right now: it's cheaper than making synthetic fuel. If fossil reserves start running low, whoppee, we'll just start making synthetic fuel. And all those gasoline or diesel cars will keep running just the same.

In fact, doing that is probably a more economical and viable way to store energy than a ton of batteries in a car.

Wow, 40% heavier and still gets the same mileage! Any other person would say this was a major improvement.

AND, the Prius is a 5 passenger car with AT-PZEV emissions. One lawn mower session puts out more emissions than a Prius after driving 500 miles. Think about the summation of health costs saved with cleaner air, besides just oil.

And take a look at this picture of your 31.4 cu.ft space Metro [consumerguide.com]. I don't see a huge cargo space behind the back seats, so it must come from folding down the seats.

Putting the flaming comment about people lying to make themselves feel better aside, the ROI for a Prius is decent. A Prius starts at about $20K so if someone "downgrades" from a larger, lower mpg car like say, a Nissan Maxima SE, s/he could feasibly save a lot of money.

We are getting 50mpg instead of 20mpg, and we no longer have to buy premium gas...we are saving $1200 a year, not counting the lower loan payments for the car we traded in.

I would go on, but I am starting to feel way, way too good about myself:-P.

The buzz today is about the miracle mileage makers called "hybrids." Wearing a Toyota Prius has become such a sought-after badge among the greenies that some dealers have been asking $5000 over the $21,290 sticker.
Does this make economic sense? Buy some other frugal car for 20 lar

Don't confuse hybrid cars (combining traditional gasoline with battery power) and pure-battery or pure-hydrogen cars.
Hybrids generally don't need to be plugged in, since they have regenerative features that recharge the battery while running.
For pure-electrical cars, which plug into the grid for juice, you are moving the pollution up the line to the power plant, as you say.
But pollution from electrical production tends to be less at the power plant end. You can pack a lot more pollution-reducing devices and processes into a large powerplant than you can with a car trying to produce it's own energy directly from, say, gas.

And it doesn't need a ton of lead for the batteries, that you would need to dispose of when the car is "retired".

That isn't nearly the issue that you think it is. Lead-acid batteries in industrial use (and, make no mistake, the batteries in hybrid cars count as industrial use) are recycled almost 100%. Realistically, probably about 98%.

Ditto with the lead-acid batteries in your UPS. Instead of throwing them away when the UPS dies, take the batteries to a local machinery shop, they'll likely take them off

Excellent point. I have a Honda Jazz GLi (in Japan, it is called the "Fit") and on a recent trip to the NSW south coast from Canberra, I got 4.2 L/100km down there and a total trip usage of 4.6 L/100km. By accelerating and slowing down slowly, I was able to cut my previous trip usage by a full litre per 100 km.

The Jazz has a 1.3 L dual spark ignition motor coupled with a CVT (Continuously Variable Transmission). It costs about 1/2 to 2/3 of a Prius. It doesn't seem to be available in in the US. Here is mo